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 *
 * \brief SHA-1 Hashing algorithm.
 * \author Giovanni Bajo <rasky@develer.com>
 */

/*
 * Derived from:
 * SHA-1 in C
 * By Steve Reid <steve@edmweb.com>
 * 100% Public Domain
 */

/* #define LITTLE_ENDIAN * This should be #define'd if true. */
/* #define SHA1HANDSOFF * Copies data before messing with it. */

#include "sha1.h"

#include <cfg/compiler.h>
#include <cfg/debug.h>
#include <cfg/macros.h>
#include <cpu/byteorder.h>  // CPU_BYTE_ORDER
#include <string.h>
#include <stdlib.h>
#include <sec/util.h>

#define SHA1_BLOCK_LEN          64
#define SHA1_DIGEST_LEN         20

static void SHA1Transform(uint32_t state[5], const uint8_t buffer[64]);

#define rol(value, bits)  ROTL(value, bits)

/* blk0() and blk() perform the initial expand. */
/* I got the idea of expanding during the round function from SSLeay */
#define blk0(i) (block[i] = be32_to_cpu(block[i]))
#define blk(i) (block[i&15] = rol(block[(i+13)&15]^block[(i+8)&15] \
                                     ^block[(i+2)&15]^block[i&15],1))

/* (R0+R1), R2, R3, R4 are the different operations used in SHA1 */
#define R0(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk0(i)+0x5A827999+rol(v,5);w=rol(w,30);
#define R1(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk(i)+0x5A827999+rol(v,5);w=rol(w,30);
#define R2(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0x6ED9EBA1+rol(v,5);w=rol(w,30);
#define R3(v,w,x,y,z,i) z+=(((w|x)&y)|(w&x))+blk(i)+0x8F1BBCDC+rol(v,5);w=rol(w,30);
#define R4(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0xCA62C1D6+rol(v,5);w=rol(w,30);


/* Hash a single 512-bit block. This is the core of the algorithm. */
static void SHA1Transform(uint32_t state[5], const uint8_t buffer[64])
{
	uint32_t a, b, c, d, e;
	uint32_t block[16];

	memcpy(&block, buffer, 64);

	/* Copy context->state[] to working vars */
	a = state[0];
	b = state[1];
	c = state[2];
	d = state[3];
	e = state[4];
	/* 4 rounds of 20 operations each. Loop unrolled. */
	R0(a,b,c,d,e, 0);
	R0(e,a,b,c,d, 1);
	R0(d,e,a,b,c, 2);
	R0(c,d,e,a,b, 3);
	R0(b,c,d,e,a, 4);
	R0(a,b,c,d,e, 5);
	R0(e,a,b,c,d, 6);
	R0(d,e,a,b,c, 7);
	R0(c,d,e,a,b, 8);
	R0(b,c,d,e,a, 9);
	R0(a,b,c,d,e,10);
	R0(e,a,b,c,d,11);
	R0(d,e,a,b,c,12);
	R0(c,d,e,a,b,13);
	R0(b,c,d,e,a,14);
	R0(a,b,c,d,e,15);
	R1(e,a,b,c,d,16);
	R1(d,e,a,b,c,17);
	R1(c,d,e,a,b,18);
	R1(b,c,d,e,a,19);
	R2(a,b,c,d,e,20);
	R2(e,a,b,c,d,21);
	R2(d,e,a,b,c,22);
	R2(c,d,e,a,b,23);
	R2(b,c,d,e,a,24);
	R2(a,b,c,d,e,25);
	R2(e,a,b,c,d,26);
	R2(d,e,a,b,c,27);
	R2(c,d,e,a,b,28);
	R2(b,c,d,e,a,29);
	R2(a,b,c,d,e,30);
	R2(e,a,b,c,d,31);
	R2(d,e,a,b,c,32);
	R2(c,d,e,a,b,33);
	R2(b,c,d,e,a,34);
	R2(a,b,c,d,e,35);
	R2(e,a,b,c,d,36);
	R2(d,e,a,b,c,37);
	R2(c,d,e,a,b,38);
	R2(b,c,d,e,a,39);
	R3(a,b,c,d,e,40);
	R3(e,a,b,c,d,41);
	R3(d,e,a,b,c,42);
	R3(c,d,e,a,b,43);
	R3(b,c,d,e,a,44);
	R3(a,b,c,d,e,45);
	R3(e,a,b,c,d,46);
	R3(d,e,a,b,c,47);
	R3(c,d,e,a,b,48);
	R3(b,c,d,e,a,49);
	R3(a,b,c,d,e,50);
	R3(e,a,b,c,d,51);
	R3(d,e,a,b,c,52);
	R3(c,d,e,a,b,53);
	R3(b,c,d,e,a,54);
	R3(a,b,c,d,e,55);
	R3(e,a,b,c,d,56);
	R3(d,e,a,b,c,57);
	R3(c,d,e,a,b,58);
	R3(b,c,d,e,a,59);
	R4(a,b,c,d,e,60);
	R4(e,a,b,c,d,61);
	R4(d,e,a,b,c,62);
	R4(c,d,e,a,b,63);
	R4(b,c,d,e,a,64);
	R4(a,b,c,d,e,65);
	R4(e,a,b,c,d,66);
	R4(d,e,a,b,c,67);
	R4(c,d,e,a,b,68);
	R4(b,c,d,e,a,69);
	R4(a,b,c,d,e,70);
	R4(e,a,b,c,d,71);
	R4(d,e,a,b,c,72);
	R4(c,d,e,a,b,73);
	R4(b,c,d,e,a,74);
	R4(a,b,c,d,e,75);
	R4(e,a,b,c,d,76);
	R4(d,e,a,b,c,77);
	R4(c,d,e,a,b,78);
	R4(b,c,d,e,a,79);
	/* Add the working vars back into context.state[] */
	state[0] += a;
	state[1] += b;
	state[2] += c;
	state[3] += d;
	state[4] += e;
	/* Wipe variables */
	a = b = c = d = e = 0;
}

static void SHA1_begin(Hash* h)
{
	SHA1_Context *context = (SHA1_Context*)h;
	/* SHA1 initialization constants */
	context->state[0] = 0x67452301;
	context->state[1] = 0xEFCDAB89;
	context->state[2] = 0x98BADCFE;
	context->state[3] = 0x10325476;
	context->state[4] = 0xC3D2E1F0;
	context->count[0] = context->count[1] = 0;
}

/* Run your data through this. */

static void SHA1_update(Hash* h, const void* vdata, size_t len)
{
	SHA1_Context *context = (SHA1_Context*)h;
	const uint8_t *data = (const uint8_t*)vdata;
	size_t i, j;

	j = (context->count[0] >> 3) & 63;
	if ((context->count[0] += len << 3) < (len << 3))
		context->count[1]++;
	context->count[1] += (len >> 29);
	if ((j + len) > 63) {
		memcpy(&context->buffer[j], data, (i = 64-j));
		SHA1Transform(context->state, context->buffer);
		for ( ; i + 63 < len; i += 64) {
			SHA1Transform(context->state, &data[i]);
		}
		j = 0;
	} else
		i = 0;
	memcpy(&context->buffer[j], &data[i], len - i);
}


/* Add padding and return the message digest. */

static uint8_t *SHA1_final(Hash* h)
{
	SHA1_Context *context = (SHA1_Context*)h;
	uint32_t i;
	uint8_t finalcount[8];

	for (i = 0; i < 8; i++)
		finalcount[i] = (uint8_t)((context->count[(i >= 4 ? 0 : 1)]
		                           >> ((3-(i & 3)) * 8) ) & 255);  /* Endian independent */

	SHA1_update(h, "\200", 1);
	while ((context->count[0] & 504) != 448)
		SHA1_update(h, "\0", 1);
	SHA1_update(h, finalcount, 8);  /* Should cause a SHA1Transform() */

	for (i = 0; i < 20; i++)
		context->buffer[i] = (uint8_t)
		                     ((context->state[i>>2] >> ((3-(i & 3)) * 8) ) & 255);

	PURGE(i);
	PURGE(finalcount);
	return context->buffer;
}


/*************************************************************/

void SHA1_init(SHA1_Context* ctx)
{
	ctx->h.block_len = SHA1_BLOCK_LEN;
	ctx->h.digest_len = SHA1_DIGEST_LEN;
	ctx->h.begin = SHA1_begin;
	ctx->h.update = SHA1_update;
	ctx->h.final = SHA1_final;
}
